JPH11295142A - Infrared image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distinguish a burning object and a high-temperature object for judging a fire and to output a monitor image excellent in visibility by selectively receiving infrared rays in two specific wavelength bands, and forming images. SOLUTION: Infrared filters 2a, 2b transmitting infrared rays in the wavelength bands of about 3-5 μm and about 8-12 μm respectively are provided in the front of an infrared detector 3 having sensitivity to the infrared rays in the wavelength bands of about 3-5 μm and about 8-12 μm The infrared filters 2a, 2b are selectively switched by a filter switching controller 4, and infrared images are picked up by the infrared detector 3. When the infrared filter 2a is selected, all wavelength bands are cut and the electric signal becomes 0 in the normal state, the presence or absence of the electric signal can be recognized in relation to the presence or absence of a fire occurrence, and the quantity of the electric signal in relation to the force of combustion. When the infrared filter 2b is selected, a high-temperature object is displayed in a high contrast, and other objects are displayed in a low contrast. The fire occurrence and high-temperature object can be distinguished from the monitor images in two wavelength bands.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared imaging apparatus for detecting infrared rays emitted when an object to be imaged is burned by a fire.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional infrared imaging apparatus of this kind. In the figure, 1 is an infrared lens that collects incident infrared rays to form an image, and 2 is an infrared filter that attenuates infrared energy. For example, when imaging a flame and smoke of an object burning by a fire,
A filter having a certain attenuation factor that allows transmission of only wavelength components near 4.5 microns is set. Reference numeral 3 denotes an infrared detector for converting incident infrared energy into an electric signal. For example, 256 infrared detection elements are horizontally and vertically arranged two-dimensionally to constitute one screen. 5 converts the imaging signal of the infrared detector 3 into a digital signal,
A video signal processing unit 6 for outputting as image data together with a video synchronization signal is
An image memory for storing image data for the screen, a binarization processing unit 7 for converting data in the image memory 6 into binary data of “1” or “0” at a certain threshold, and a binary processing unit 8 A measurement unit that measures information necessary for determining the presence or absence of a fire from the data of the unit 7, and measures feature amount data of a portion of the binary data that has been converted to “1” as a united region. Reference numeral 9 denotes an instruction to write data to the image memory 6 and a setting of threshold data to the binarization processing unit 7, and determines whether or not there is a fire from the measurement information of the measurement unit 8, and outputs fire detection information to an external device. Processor.

Next, an operation example will be described. The infrared ray that has entered the infrared lens 1 transmits only a wavelength component near 4.5 microns through the infrared filter 2 and is further attenuated before reaching the infrared detector 3. The optical characteristics of the infrared filter 2 are such that the infrared detector 3 emits strong infrared energy having a peak at about 4.5 μm, which is generated by carbon monoxide or carbon dioxide generated by burning of the object in the event of a fire. In the event of a fire, the infrared energy of about 4.5 microns maintains a sufficient amount of light even after passing through the infrared filter 2 and is transmitted to the infrared detector 3 in the event of a fire. To reach,
The infrared detector 3 can obtain an electric signal corresponding to the infrared radiation energy generated by the combustion. In a steady state where no fire occurs, the radiant energy near 4.5 microns is weaker than when a flame occurs. Therefore, the infrared energy in all wavelength bands is cut by the infrared filter 2 and the infrared detector 3 Can be made substantially zero. That is, the presence or absence of an electric signal from the infrared detector 3 can be recognized as the presence or absence of a fire, and the amount of the electric signal can be associated with the momentum and magnitude of combustion.
The electric signal obtained by the infrared detector 3 is subjected to video signal processing similar to that of a normal television camera in the video signal processing unit 5, and is output as digital real-time image data of, for example, 30 screens per second. This image data is stored in the image memory 6 according to an instruction from the processor 9. The image memory 6 has, for example, a capacity to store image data of 256 pixels in each of the horizontal and vertical directions for one screen, and is configured to be able to write image data in units of one screen in accordance with an instruction from the processor 9. The image data stored in the image memory 6 is converted to binary data of “1” or “0” at a threshold value of the binarization processing unit 7. Here, the certain threshold value is a luminance value at a boundary of whether or not it is recognized that carbon monoxide or carbon dioxide has been generated by combustion, and the value is set by the processor 9. For example, when the image data has 256 gradations, a value of 127 or less of each pixel is set to “0” as noise or not to be detected, and a value of 128 or more is set to “1” as apparently burning. Work. Next, the image data of the burning object extracted by the binarization processing unit 7 is characterized by the measurement unit 8 such as the number of pixels, the shape, the coordinates, and the like of the pixels of the portion set as “1” as a united region. Converted to data. It should be noted that in a steady state when no fire occurs, there is no pixel set to “1”, and therefore, the feature amount data is significantly different from that obtained by measuring a burning object. As described above, based on the information obtained by the measurement unit 8, the processor 9 calculates the presence / absence, scale, occurrence position, and the like of the fire in the monitored area, and determines that a fire has occurred after comprehensive judgment. In this case, an alarm is issued to an externally connected device.

[0004]

As described above, the conventional infrared imaging apparatus detects the presence or absence of a flame by associating infrared energy near 4.5 microns with combustion by a fire as described above. When an image of a high-temperature object having the same or higher thermal radiation energy in this wavelength band is taken, there is a problem that it is difficult to distinguish it from a fire. FIG. 5 shows the spectral radiation characteristics of a hot object and a flame quoted from “Research Report on Firefighting Measures for Large-Scale Buildings and Unique Buildings” published by the Tokyo Fire Department. It shows that the spectrum has a peak in the amount of spectral radiation around 5 microns. Therefore, according to the conventional method,
For example, when a high-temperature object that is not a detection target, such as an exhaust pipe of a car or a strong illumination light, exists in the field of view, these are determined to be fires and a false alarm is issued. In addition, if there is no fire or high-temperature object, no image can be obtained at all, and even if it does exist, the surrounding image cannot be obtained. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to distinguish between a burning object and a high-temperature object so as to judge a fire and to provide a surveillance image with excellent visibility. An object of the present invention is to provide an infrared imaging device capable of outputting.

[0006]

According to the first aspect of the present invention, there is provided an infrared imaging apparatus having three infrared rays in front of an infrared detector having sensitivity to infrared rays of 3 to 5 microns band and infrared rays of both wavelengths of 8 to 12 microns band. An infrared filter that transmits infrared light in the micron to 5 micron band and an infrared filter that transmits infrared light in the 8 to 12 micron band, and further selects these infrared filters, and detects the infrared light that has passed through the selected infrared filter to the infrared detector Infrared filter selection means for receiving light is provided so that an infrared image can be captured for each wavelength band.

A second aspect of the present invention provides an infrared imaging apparatus which stores an infrared video signal of any of the 3 to 5 micron band or 8 to 12 micron band as a digital video signal and a digital video signal. The apparatus is provided with means for binarizing, and the presence or absence of a fire is determined by comparing feature values such as the number of pixels, the shape, and the coordinates in the binary image data of both wavelength bands.

The infrared imaging apparatus according to a third aspect of the present invention is an image memory for storing the infrared video signals of both the 3 μm to 5 μm band and the 8 μm to 12 μm band as digital video signals, and is stored in the image memory. Means for superimposing and synthesizing the digital video signal for each wavelength band as one video so as to output a composite infrared video of both wavelength bands.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is an example showing Embodiment 1 of the present invention.
5 performs the same function as the conventional device. 2a is an infrared filter having a certain attenuating factor that transmits only a wavelength component near 4.5 microns similar to the conventional device, 2b is an infrared filter that transmits a wavelength component of 8 to 12 microns, 4 is an infrared filter 2a or Infrared filter 2
b is a filter switching control unit that mechanically switches and selects one of the filters.

Next, an operation example will be described. In the infrared imaging device of the present invention configured as described above, when the infrared filter 2a is selected by the filter switching control unit 4, the infrared light incident on the infrared lens 1 is transmitted by the infrared filter 2a in the same manner as in the conventional device. 4.5
Only the wavelength component near the micron is transmitted, further attenuated, and reaches the infrared detector 3. Thereby, the infrared detector 3 can obtain an electric signal corresponding to the infrared radiation energy generated by the combustion. In a steady state in which no fire occurs, the infrared energy in all wavelength bands is cut by the infrared filter 2a, and the electric signal obtained by the infrared detector 3 can be made substantially zero. That is,
The presence or absence of an electric signal from the infrared detector 3 can be recognized as the presence or absence of a fire by associating the amount of the electric signal with the momentum or magnitude of combustion. Next, when the infrared filter 2 b is selected by the filter switching control unit 4, only the wavelength component of 8 μm to 12 μm is transmitted by the infrared filter 2 b and reaches the infrared detector 3. The optical characteristics of the infrared filter 2b are intended to allow the infrared detector 3 to capture only infrared energy of about 8 to 12 microns emitted from a high-temperature object. The strong infrared energy of about 12 microns is output from the infrared detector 3 as a relatively large electric signal. However, when a fire mainly composed of carbon monoxide or carbon dioxide is occurring or when there is no high-temperature object, the infrared energy in the vicinity of 8 to 12 microns is slightly weaker than that of a high-temperature object, The electrical signal obtained by the detector 3 is relatively small.
That is, a high-temperature object is imaged with high contrast, and the others are imaged with low contrast. As described above, the electric signal output from the infrared detector 3 obtained by switching the infrared filter 2a and the infrared filter 2b is subjected to video signal processing similar to that of a normal television camera in the video signal processing unit 5, for example, It is output as digital real-time image data of 30 screens per second. As a result, infrared images can be obtained in the vicinity of 4.5 microns or in the wavelength band of 8 to 12 microns. If these images are displayed on, for example, a television monitor, the observer can visually compare the images and detect a fire. And hot objects can be distinguished.

Embodiment 2 FIG. 2 is an example showing Embodiment 2 of the present invention.
Reference numerals 3 to 9 perform the same functions as those of the conventional device or the first embodiment of the present invention.

Next, an operation example will be described. In the infrared imaging apparatus of the present invention configured as described above, when the infrared filter 2a is selected by the filter switching control unit 4, it is the same as the conventional apparatus or the first embodiment of the present invention. The incident infrared light
Since only wavelength components around 4.5 microns are transmitted and attenuated, strong infrared energy with a peak around 4.5 microns emitted by carbon monoxide and carbon dioxide at the time of fire and strong infrared radiation emitted by high temperature objects Only the energy reaches the infrared detector 3 and is converted into an electric signal.
In addition, when no fire has occurred and no high-temperature object exists, the electric signal obtained by the infrared detector 3 becomes almost zero. The electric signal obtained by the infrared detector 3 is converted into image data by the video signal processing unit 5 and stored in the image memory 6. The data of each pixel output from the image memory 6 is set to “0” or “1” by the binarization processing unit 7 at a threshold value of whether or not to recognize the object as a fire or a high-temperature object. The binary data extracted by the binarization processing unit 7 is
The measurement unit 8 converts the data into feature data such as the number, shape, and coordinates of pixels, and the processor 9 reads this value. The operation up to this point is the same as that of the conventional apparatus, but in the infrared imaging apparatus of the present invention, it is determined whether this series of processing is mainly composed of carbon monoxide and carbon dioxide due to a fire or a high-temperature object not to be detected. In order to make a determination, the following operation is performed in the same manner as in the first embodiment of the present invention without issuing an alarm. When the processor 9 observes a fire or a high-temperature object in the processed image near 4.5 microns, the processor 9 controls the filter switching control unit 4 to select the infrared filter 2b. The case where the infrared filter 2b is selected is the same as the case of the infrared filter 2a, and the electric signal obtained by the infrared detector 3 is
It is stored in the image memory 6 via the video signal processing unit 5. The data of each pixel output from the image memory 6 is set to “0” or “1” by the binarization processing unit 7 at a threshold of whether or not to recognize the object as a high-temperature object. The binary data extracted by the binarization processing unit 7 is converted into feature amount data such as the number, shape, and coordinates of pixels by the measurement unit 8, and the processor 9 reads this value. Next, the processor 9 compares the 4.5 μm feature amount data obtained by the above operation with the 8 μm to 12 μm feature amount data at the same coordinates in the image space. If both image data are "0", it is determined that no fire has occurred and no high-temperature object exists. If the value is "1" in the image data of 4.5 microns and "0" in the image data of 8 to 12 microns, it is determined that carbon monoxide or carbon dioxide has been generated due to the occurrence of a fire. Further, when both image data are “1”, it is determined that only a high-temperature object is present and no carbon monoxide or carbon dioxide is generated. The processor 9 performs the above-described comparison processing while alternately switching between the infrared filter 2b and the infrared filter 2c, and connects to the outside only when it is determined that carbon monoxide or carbon dioxide is generated due to the occurrence of a fire. An alarm is issued to the connected device.

Embodiment 3 FIG. 3 is a diagram showing Embodiment 2 of the present invention, in which 1 to 5 and 7 to 9 are:
It performs the same function as that of the first embodiment of the present invention. Also,
6a is an image memory 6 according to the first embodiment of the present invention.
Performs the same function as. Reference numeral 6b denotes an image memory for storing an infrared image of 8 to 12 microns, one screen at a time.
Numeral 0 denotes a superimposition synthesizing unit for synthesizing the images of 4.5 μm and 8 μm to 12 μm output from the image memory 6b and synthesizing them into one video. This is a video output unit for outputting as a video.

Next, an operation example will be described. 3. In the infrared imaging device of the present invention configured as described above,
The method of comparing the infrared images of the wavelength bands of 5 microns and 8 microns to 12 microns by alternately switching the infrared filter 2a and the infrared filter 2b to determine a fire or a hot object is the same as in the first embodiment of the invention. It is.
The embodiment of the present invention is obtained by adding the following operation to the above. When the processor 9 selects the infrared filter 2a and performs image measurement in this wavelength band,
The image data of the wavelength band of 4.5 microns output from the video signal processing unit 5 is stored in the image memory 6b. Here, the image memory 6b stores, for example, 256 pixels horizontally and vertically.
It has a capacity to store image data of pixels for two screens, and is configured to be able to store image data for one screen for each of 4.5 μm and a wavelength band of 8 μm to 12 μm according to an instruction of the processor 9. When the storage of the 4.5-micron image data is completed, the processor 9 switches to the infrared filter 2b while keeping this data.
In this state, the image data of the wavelength band of 8 to 12 microns output from the video signal processing unit 5 is stored in the image memory 6.
b is stored in the remaining half area. When the storage of the image data of 8 to 12 microns is completed, the processor 9
Gives a read control signal to the image memory 6b,
The data for the screen is simultaneously read and sent to the superimposing / synthesizing unit 10. The superposition / synthesis unit 10 is a so-called look-up table, and has a function of changing the contrast and brightness of a portion of the image data in the wavelength band of 8 to 12 microns to be emphasized by multiplying by an arbitrary coefficient. For example, if a value obtained by dividing the luminance value of the image data of 4.5 microns by a certain value and multiplying the image data of the wavelength band of 8 to 12 microns is obtained, no fire has occurred and a high-temperature object exists. In this case, an image of about 8 to 12 microns is output as it is. However, if carbon monoxide or carbon dioxide is generated by a fire, the brightness of the generated area may be enhanced and output. it can. The superimposed image output from the superposition / synthesis unit 10 is output from the video output unit 11 as a normal television video signal.

[0015]

As described above, according to the first invention, the generation of carbon monoxide and carbon dioxide due to a fire and the object to be detected from the infrared images in the wavelength bands of 3 to 5 microns and 8 to 12 microns. The outside high-temperature object can be visually distinguished and determined.

According to the second aspect of the present invention, from 3 microns
Compares the intensity of infrared images in the 5 micron and 8 micron to 12 micron wavelength bands by image signal processing, and automatically distinguishes between carbon monoxide and carbon dioxide generated by fire and high-temperature objects that are not detected. Since the judgment can be made, labor saving of the monitor can be achieved, and false alarms to the externally connected devices can be reduced.

Further, according to the third aspect of the present invention, it is possible to visualize images from room temperature to high temperature, which is a feature of an image of 8 to 12 microns, and particularly sensitive to fire, which is a feature of an image of 4.5 microns. It is possible to synthesize an image having both of the points having the above, and to provide an image in which the monitoring target can be easily visually grasped.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is a diagram showing a conventional infrared imaging device.

FIG. 5 is a diagram showing spectral emission characteristics of a hot object and a flame.

[Explanation of symbols]

1 infrared lens, 2 infrared filter, 2a infrared filter, 2b infrared filter, 3 infrared detector,
4 filter switching control unit, 5 video signal processing unit, 6
Image memory, 6a image memory, 6b image memory,
7 Binarization processing unit, 8 Measurement unit, 9 Processor, 10
Superimposition synthesis unit, 11 video output unit.

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H04N 5/33 H04N 5/33

Claims (3)

[Claims] 1. An infrared imaging apparatus which detects infrared rays emitted from an object to determine the presence or absence of a fire.
An infrared detector having sensitivity to a first infrared ray in a micron band, a second infrared ray in an 8 to 12 micron band, a first infrared filter transmitting the first infrared ray, and a second infrared ray. A second infrared filter that transmits light; and an infrared filter selection unit that selects the first and second infrared filters and causes the infrared detector to receive infrared light in a wavelength band transmitted through the selected infrared filters. An infrared imaging device characterized by the above-mentioned. 2. The first signal output from the infrared detector.
A video signal processing unit for converting first and second analog signals corresponding to a second infrared ray into first and second digital video signals, and first and second digital signals converted by the video signal processing unit An image memory that stores a video signal, a binarization processing unit that binarizes the first and second digital video signals stored in the image memory, and a binarization unit that is binarized by the binarization processing unit. 1, the first corresponding to the second digital video signal,
2. The infrared imaging apparatus according to claim 1, further comprising: a determination unit configured to compare feature amounts of the second binary data, such as the number of pixels, a shape, and coordinates, and determine whether there is a fire based on the comparison result. . 3. A second image memory for storing first and second digital video signals, and a superposition / synthesis unit for synthesizing the first and second digital video signals stored in the second image memory. 3. The infrared imaging apparatus according to claim 2, further comprising: a video output unit that converts a superimposed image synthesized by the superimposition synthesis unit into a television video signal.